Düker is a family-owned company based in Karlstadt (near Würzburg) in Northern Bavaria. The company's origins can be traced back to the year 1469.

The company manufactures various products made of cast iron in its two foundries in Karlstadt and Laufach, among them pipes, fittings and valves for water, waste water and gas. Dueker is the only EN 877 cast iron pipe manufacturer in Germany.